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What a difference a year makes

In one short month, Mammoth and the Eastern Sierra broke out of a year-long drought and landed squarely in the middle of an average winter—at least so far.

As of Jan. 2, Mammoth Pass was at about 50 percent of its average moisture for the entire winter, and at about 100 percent of the average amount of moisture it normally gets as of that date, according to Los Angeles Department of Water and Power data.

The pass averages about 42 inches of water content a winter, and roughly 40 feet of snow (snow depth is very fungible, often changing daily due to settling and/or melting. Water content in that snow, however, is a constant).

Right now, the pass has about 22 inches of water and roughly 15 feet of snow, according to state Department of Water Resources data.

The pass has thus received about half of the precipitation that it normally gets between Dec. 1 and March 30 (the four-month time frame where the state and DWP measure mountain snowfall).

There is still plenty of time for this rosy scenario to go bad. It could stop snowing for the rest of the season, leaving the Eastern Sierra high and dry.

The numbers could also go backward. If it doesn’t snow for a significant number of weeks, the percentages will steadily decrease as time passes.

‘Time is on our side’

The presence of so much snow means the area has something it didn’t have last year—something no one is taking for granted.

Time.

“Time is on our side,” said Frank Gehrke, the chief hydrologist for the state. “The Sierra’s normally wettest months (February through March) are still ahead, and that gives us three good months to make it to normal or above.”

The big question now is, “When’s the next storm?”

According to the National Weather Service, not for a while.

Dry and cold air is expected for at least the next week, maybe two. The strong high-pressure ridge over the Sierra also means air quality is likely to decrease, as there is little energy in the region to mix the air and clean it out.

The service forecast indicated temperatures will continue to be colder than normal, at least for the next few days. As the rest of the region shivers in the single digit and below zero temperatures this week, however, Mammoth Lakes broke 45 degrees yesterday (according to a thermometer on Old Mammoth) and streets began to melt for the first time in a week.

According to Mammoth’s amateur weather forecaster Howard Sheckter, there’s a reason for that. Mammoth is in the “banana belt” of the Sierra.

“Here is the trick,” Sheckter said a recent email. “Usually when you look at the high temperature spreads for Mono County, you will see spreads like 32 (degrees) to 42 (degrees) or something of the sort. Most folks figure that the low temps are for the upper elevation. Not so. When there is snow cover throughout Long Valley (and) north to Bridgeport and it is December/January and we are under an upper ridge, the warmest temps are at 8,000 feet. We live in the winter’s Banana Belt, usually found between 8,000 and 8,500 feet.”

This phenomenon is due to the fact that cold air is heavier than warm air, and Mammoth lies midway up the mountains, instead of down in a valley, like Crowley Lake and Bridgeport.